1. Field of the Invention
This invention relates to a process for degrading high polymers and more particularly to a process for destroying a shaped article made of a high polymer for easy waste disposal.
2. Description of the Prior Art
In response to demands for shaped articles made of synthetic polymers, i.e., plastic products which possess excellent durability for use including in the outdoors, their production has been recently increased remarkably and this has been accompanied by an increase of waste products thereof. The durability of shaped articles made of such a polymer may be easily seen from the fact, for example, that a sheet of plasticized polyvinyl chloride of 0.08 mm in thickness for agricultural use can be first manually crushed after the sheet is oxidized for 1,200 hours in air at 45.degree. C. under ultraviolet radiation emitted from a high pressure mercury vapor lamp of 1.2 K. watts capacity spaced from the sheet at a distance of 50 cm. This high durability which is desired when the plastic products are in practical use, causes a very serious problem of waste disposal thereof. It is very urgent to solve this problem in order to prevent environmental pollution, since natural decay thereof can hardly be expected.
For this purpose, there have been studied and proposed many processes including mechanical crushing, application of chemicals, subjecting to photo-oxidation, biodegradation using a microorganism and incineration, all of which have, however, individual deficiencies. For example, an attempt has been made which comprises incorporating a ketone compound into a high polymer and subjecting the polymer to irradiation of light in the presence of ambient oxygen to cause oxidation of the polymer, whereby the polymer is degraded. However, this process using the saturated or unsaturated ketone compound such as acetone or methyl vinyl ketone still involves a disadvantage that the oxidation rate of the polymer is extremely slow.